WHO director-general Tedros Ghebreyesus said he chose to rescind his appointment of Mr Mugabe, 93, after listening to the flood of outrage and concerns voiced by worldwide leaders and health experts.
Simon Harris was among those who slammed the appointment describing it as freakish and offensive. Mugabe also faces US sanctions over his government's human rights abuses.
"We have registered our concerns with WHO Director General Dr. Tedros Adhanom Ghebreyesus", a foreign office spokesperson said in an email.
WHO chief Tedros Adhanom Ghebreyesus said he chose to rescind his appointment of Mugabe, 93, after listening to the flood of outrage and concerns voiced by global leaders and health experts. Kenneth Roth, the head of Human Rights Watch, tweeted: 'Mugabe corruption decimates Zimbabwe health care'.
Speaking on the BBC's Today programme, Nigel Evans, a UK Conservative MP and member of the International Development Select Committee, said: "I find it astonishing and reprehensive that the World Health Organization has done this".
With Mugabe on hand, Tedros announced the appointment at a conference in Uruguay this week on non-communicable diseases.
He had previously praised Zimbabwe for its commitment to public health. A World Health Organization spokeswoman confirmed the comments to The Associated Press.
"The government of Robert Mugabe has brutalised human rights activists, crushed democracy dissidents, and turned the breadbasket of Africa and its health system into a basket-case", he said. They also can be fired.
Zimbabwe's government hasn't commented on the appointment, but the state-run Zimbabwe Herald newspaper called it a "new feather in the president's cap".
The southern African nation once was known as the region's prosperous breadbasket.
"The government of Robert Mugabe presided over the dramatic reversal of its population's access to food, clean water, basic sanitation and health care", the group concluded.
But activists inside the country said it was "absurd" to give the role to Mugabe, who has been accused of ruining his country's health system and regularly flies overseas for his own medical treatment.